Natural Background Enhancement Needed

I have one photo that currently looks obviously edited, mainly because the setting behind the subject feels artificial. I’d like the background re-worked so it blends in convincingly—subtle, cohesive, and free from any tell-tale “Photoshop” look. The core task is to add realistic natural elements that match the existing light, depth, and color, making the entire scene appear as though it was captured that way in camera.

Please show examples of similar retouching you’ve done before; past work is the key factor I’ll use when choosing the freelancer. Once we agree on the direction, I’ll supply the high-resolution original and notes about the environment I’m aiming for. The final deliverable should be a high-res JPEG plus a layered PSD (or equivalent) so small tweaks remain possible.